This invention relates to a device for inserting a flexible member into a living body, more particularly, for inserting a flexible member through a helically formed hollow needle.
A flexible, electrically conductive member is often used as an electrode for Functional Electrical Stimulation. Such member may be a regular electrode, a shape memory alloy or an electroactive polymer. Needle insertion into soft tissue is probably the most common surgical procedure for either therapeutic drug deliver or tissue sample removal from deep within the body. Hollow needles can also be used to implant electrodes or other members which fit through the lumen. Such needles are predominantly straight. For some procedures, needles can be bent in a preferred way, however, there are far fewer implanting procedures which involve helices. Devices and methods for medical inserting procedures, which make use of the helix, are known in the prior art. For example, tips of cardiac electrodes are often formed as a helix for the purpose of anchoring one end to a muscle of the heart, for example, the myocardium. The helix/coil at the end of the electrode is used to screw and hold it in place. There are several procedures which rely on the same basic tissue anchoring mechanism to affix an inserted member to a specific tissue location. There are even endoscopical procedures, such as described in U.S. patent application Ser. No. 12/363,137, to Fox, entitled SURGICAL DEVICE, the content of which is incorporated herein by reference thereto, which, during surgery, only temporarily fixes an overtube to an organ wall using a helical anchoring mechanism.
Still further, there are procedures involving helical needles for the delivery for fluids. As an example, in U.S. Pat. No. 7,309,325 to Mulier et al, entitled HELICAL NEEDLE APPARATUS FOR CREATING A VIRTUAL ELECTRODE USED FOR THE ABLATION OF TISSUE, the content of which is incorporated herein by reference thereto, a helical needle is used to deliver a conductive fluid to a target site.
U.S. patent application Ser. No. 11/834,186, to Rioux, entitled CORKSCREW HELICAL INSERTER PORT, the content of which is incorporated by reference hereto, describes a method and a device for inserting a helical member into a septum for injection or extraction of fluid therein. The device may include a handle having an actuator lever rotatably coupled thereto. The device may also include a helical member which has a tissue piercing distal tip. The helical member is coupled to the handle via a linkage operating so that, as the actuator lever is rotated in a first direction relative to the handle, the helical member is rotated and moved distally to screw into tissue along a substantially helical path.
In U.S. Pat. No. 7,637,918, to Dant, entitled HELICAL SUTURING DEVICE, the content of which is incorporated by reference hereto, a helical hollow needle is used to helically insert a suture, which is retrieved at one end with a straight retriever along the axis of the helix.
Nevertheless, what is needed is an inserter, which can insert an electrode or a shape memory alloy into soft tissue through a helical hollow needle along a helical punctured pathway and do so quickly, safely and precisely, so as to minimize or eliminate drift or wander. Furthermore, if the member inserted must maintain a desired orientation with respect to the tissue of the punctured pathway, a mechanism is needed which ensures precise delivery without twisting of the member, as the needle withdraws from the pierced tissue.
Still further, what is needed is a method of inserting a flexible member in soft tissue precisely along a predefined helical path, with a mechanism, which can push said member out of a helical hollow needle when withdrawing it, with said member maintaining its orientation with respect to the tissue.